A5001581010- Hydrogen Storage and Materials
- Carbon Dioxide Capture Technologies
- Membrane Separation and Gas Transport
- Catalytic Processes in Materials Science
- Zeolite Catalysis and Synthesis
- Ammonia Synthesis and Nitrogen Reduction
- Carbon dioxide utilization in catalysis
- Superconductivity in MgB2 and Alloys
- Boron and Carbon Nanomaterials Research
- Advanced Battery Materials and Technologies
- MXene and MAX Phase Materials
- Advancements in Battery Materials
- Metal-Organic Frameworks: Synthesis and Applications
- Covalent Organic Framework Applications
- Catalysis and Oxidation Reactions
- Advanced NMR Techniques and Applications
- Phase Equilibria and Thermodynamics
- Catalysts for Methane Reforming
- Electrocatalysts for Energy Conversion
- Machine Learning in Materials Science
- Quantum, superfluid, helium dynamics
- Advanced Battery Technologies Research
- Nanomaterials for catalytic reactions
- Recycling and Waste Management Techniques
- Chemical Synthesis and Characterization
Lawrence Livermore National Laboratory
2020-2025
University of Notre Dame
2017-2023
Colorado School of Mines
2023
National Renewable Energy Laboratory
2023
Lawrence Berkeley National Laboratory
2020
Copper ions exchanged into zeolites are active for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) with ammonia (NH3), but low-temperature rate dependence on copper (Cu) volumetric density is inconsistent reaction at single sites. We combine steady-state and transient kinetic measurements, x-ray absorption spectroscopy, first-principles calculations to demonstrate that under conditions, mobilized Cu can travel through zeolite windows form ion pairs participate in an oxygen...
We combine experiment and theory to investigate the cooperation or competition between organic inorganic structure-directing agents (SDAs) for occupancy within microporous voids of chabazite (CHA) zeolites rationalize effects SDA siting on biasing framework Al arrangement (Al–O(−Si–O)x–Al, x = 1–3) among CHA essentially fixed composition (Si/Al 15). crystallized using mixtures TMAda+ Na+ contain one occluded per cage co-occluded in an amount linearly proportional number 6-MR paired sites,...
Metal ions exchanged on zeolites represent a unique bridge between heterogeneous solid materials and homogeneous inorganic chemistry. The complexing of metal with H2O or NO, is particular relevance for number reactions, including the ubiquitous presence both gases in pollution remediation technologies. Here, we interrogate molecular structure Pd cations SSZ-13 their interaction NO using experimental computational analyses. Density functional theory (DFT) spectroscopic characterization...
Abstract Intense literature and research efforts have focussed on the exploration of complex hydrides for energy storage applications over past decades. A focus was dedicated to determination their thermodynamic hydrogen properties, due high gravimetric volumetric capacities, but application has been limited because harsh working conditions reversible release uptake. The present review aims at appraising recent advances different hydride systems, coming from proficient collaborative...
Experiments and density functional theory (DFT) models are combined to develop a unified, quantitative model of the mechanism kinetics fast selective catalytic reduction (SCR) NO/NO2 mixtures over H-SSZ-13 zeolite. Rates, rate orders, apparent activation energies collected under differential conditions reveal two distinct kinetic regimes. First-principles thermodynamics simulations used determine relative coverages free Brønsted sites, chemisorbed NH4+, physisorbed NH3 as function reaction...
Aminopolymer-based sorbents are preferred materials for extraction of CO2 from ambient air [direct capture (DAC) CO2] owing to their high adsorption capacity and selectivity at ultra-dilute conditions. While those adsorptive properties important, the stability a sorbent is key element in developing high-performing, cost-effective, long-lasting that can be deployed scale. Along with process upsets, environmental components such as CO2, O2, H2O may contribute long-term instability. As such,...
Metal-exchanged zeolites are common catalysts and adsorbents, but the relationship between their macroscopic composition (Si:Al M:Al ratios) microscopic details of exchange site reactivity difficult to infer. Here we address this general problem for Fe in an SSZ-13 zeolite. We report periodic supercell density functional theory (DFT) calculations structures energies candidate Fe-exchange sites, including monomeric dimeric species with formal oxidation states ranging from 2+ 5+...
A general problem when designing functional nanomaterials for energy storage is the lack of control over stability and reactivity metastable phases. Using high-capacity hydrogen candidate LiAlH4 as an exemplar, we demonstrate alternative approach to thermodynamic stabilization metal hydrides by coordination nitrogen binding sites within nanopores N-doped CMK-3 carbon (NCMK-3). The resulting LiAlH4@NCMK-3 material releases H2 at temperatures low 126 °C with full decomposition below 240 °C,...
Lithium metal is a promising high-capacity anode material for solid-state batteries, but it typically suffers from poor cyclability. Carbon scaffold hosts have the potential to improve this performance due their high electronic conductivity and large surface area, which facilitates lithium-ion adsorption desorption. Scaffold chemistry known significantly influence outcomes, details of these interactions are not fully understood. This study employs first-principles simulations explore lithium...
The relative proximity of Al atoms substituted in zeolite lattices is an important parameter that influences both hydrothermal stability and catalytic function, but the underlying chemistry governs site not well understood. Here, we examine relationships between exchanged countercations different Al–Al arrangements a chabazite (SSZ-13) lattice. We report periodic supercell density functional theory (DFT) calculations for structures energies SSZ-13 with systematically enumerated varied...
Poly(ethyleneimine) (PEI)-based CO2 sorbents are a promising material class for use in capture applications, particularly direct air (DAC), due to their high amine content and capacities. The sorbent lifetime is key uncertainty the deployment of these materials such as they oxidize under conditions relevant candidate DAC process cycles. Here, we utilize thermogravimetric analysis/differential scanning calorimetry/FTIR spectroscopy characterize nature, rate, quantity volatile species formed...
Metal boride nanostructures have shown significant promise for hydrogen storage applications. However, the synthesis of nanoscale metal particles is challenging because their high surface energy, strong inter- and intraplanar bonding, difficult-to-control termination. Here, it demonstrated that mechanochemical exfoliation magnesium diboride in zirconia produces 3-4 nm ultrathin MgB2 nanosheets (multilayers) yield. High-pressure hydrogenation these multilayers at 70 MPa 330 °C followed by...
Combined modeling and experiments uncover the influence of epoxide-functionalization on hydrogen bonding mobility within poly(ethylenimine) CO 2 sorbents, rationalizing antidegradation benefits conferred by functionalization.
Layered boron compounds have attracted significant interest in applications from energy storage to electronic materials device applications, owing part a diversity of surface properties tied specific arrangements atoms. Here we report the landscape for atomic configurations MgB2 by combining first-principles calculations, global optimization, material synthesis and characterization. We demonstrate that contrary previous assumptions, multiple disordered reconstructions are thermodynamically...
Amine-based adsorbents are promising for direct air capture of CO2 , yet oxidative degradation remains a key unmitigated risk hindering wide-scale deployment. Borrowing wisdom from the basic auto-oxidation scheme, insights gained into underlying mechanisms polyamines by quantum chemical, advanced sampling simulations, adsorbent synthesis, and accelerated experiments. The reaction kinetics contrasted with that typical aliphatic polymers they elucidate first time critical role aminoalkyl...
Structure-directing agents (SDAs) influence not only zeolite structures but also the distribution of Al on lattices. The origins this Al-directing are well understood. Here, we use first-principles methods to explore interactions between an N,N,N-trimethyl-1-adamantyl ammonium (TMAda+) OSDA and framework [AlO2]− in dilute limit within SSZ-13 lattice. Molecular dynamics geometric electronic illuminate rotational freedom TMAda+ cage, primarily electrostatic nature its with [AlO2]−, effect...
Metal borides have attracted the attention of researchers due to their useful physical properties and unique ability form high hydrogen-capacity metal borohydrides. We demonstrate improved hydrogen storage a nanoscale Mg–B material made by surfactant ball milling MgB2 in mixture heptane, oleic acid, oleylamine. Transmission electron microscopy data show that nanoplatelets are produced with sizes ranging from 5 50 nm, which agglomerate upon ethanol washing produce an agglomerated micron-sized...
Abstract The highly unfavorable thermodynamics of direct aluminum hydrogenation can be overcome by stabilizing alane within a nanoporous bipyridine‐functionalized covalent triazine framework (AlH 3 @CTF‐bipyridine). This material and the counterpart AlH @CTF‐biphenyl rapidly desorb H 2 between 95 154 °C, with desorption complete at 250 °C. Sieverts measurements, 27 Al MAS NMR Al{ 1 H} REDOR experiments, computational spectroscopy reveal that @CTF‐bipyridine dehydrogenation is reversible 60...
Amine-functionalized porous solid materials are effective sorbents for direct air capture (DAC) of CO
Metal hydrides are attractive for compact, low-pressure hydrogen storage, yet a foundational understanding of factors governing their thermodynamics and kinetics is still lacking. Predictive modeling from the atomic to microstructural scale plays critical role in addressing these gaps, particularly nanoscale materials, which promise improved performance but difficult probe. Here, we summarize strategies being developed within Hydrogen Materials—Advanced Research Consortium (HyMARC) going...
Pd-catalyzed reduction has emerged as a promising treatment strategy to remove the recalcitrant disinfection byproduct N-nitrosodimethylamine (NDMA). However, reaction pathways remain unexplored, and questions about how water solvent influences NDMA mechanisms selectivity. Here, we compute energies barriers of all relevant elementary steps in by H2 on Pd(111) using density functional theory. We further calculate water-assisted H-shuttling for hydrogenation reactions explicitly include...